The long-term objective of this research is to advance the use of decision analysis in biosurveillance. The disease surveillance staff in a health department face an increasing number of high-stakes decisions under uncertainty and time pressure. This situation is in part due to the threat of bioterrorism and emerging diseases and in part a result of new surveillance systems they have constructed. These systems collect less diagnostically precise--but earlier--surveillance data in an effort to detect disease outbreaks as early as possible. The specific aims of the research are to (1) construct decision analyses of representative bio-surveillance decision problems using standard decision analytic techniques, and (2) deploy the underlying decision models in a decision-support system for analysts and epidemiologists. The research has the potential to improve the speed and efficacy of public health response to outbreaks and thereby potentially reduce morbidity and mortality. The research also has the potential to increase the efficiency of bio-surveillance systems by providing a basis for rational setting of alarm thresholds.